Method of inhibiting the alkaline corrosion of tin containers



Patented Apr. 4, 1939 UNITED STATES METHOD OF INHIBITING THE CORROSION QF TIN CONTAINERS Anthony C. Nitti, Brooklyn, N. Y., assignor to E. R. Squibb & Sons, New York, N. Y., a corporation of New York No Drawing. Application December 9, 1938, Serial No. 114,952

7 Claims.

This invention relates to alkaline preparations packed in tin containers, which term is used herein to embrace containers made of, or internally coated with, tin or alloys of tin, especially tin-coated iron cans, tin-coated lead collapsible tubes, and tin collapsible tubes.

When alkaline preparations are packed in tin containers, there occurs an interaction (increasing with lapse of time and elevation of temperature) which tends to bring about corrosion of the tin container and alteration of the alkaline preparationa conspicuous instance of this alteration being the fading of phthalein dyes present in the alkaline preparation as coloring.

To avert such interaction, certain chemical agents and mechanical expedients (including linings of wax, rubber, and other inert materials) have been employed heretofore, but they either did not achieve the desired result or else introduced troublesome contaminating substances or entailed undue difiiculty or expense.

It is an object of this invention to provide'a simple and efiicient method of minimizing such interaction; and it is a further object to provide a package comprising a. tin container having therein an alkaline preparation so constituted as practically to eliminate the likelihood of such corrosionor alteration.

In the practice of this invention, there is incorporated into alkaline preparations to be packed in tin containers an iodide of an element selected from the group consisting of alkali metals and the alkaline-earth metals; notably the iodides of potassium, sodium, calcium, and magnesium.

A small proportion of these iodides suffices to eliminate the likelihood of, or at least to postpone for a very long period of time, appreciable interaction between alkaline preparations and tin containers in which they are packed.

Among the preparations to which the invention is applicable are foods, medicines, pharmaceuticals, and cosmetics; particularly dentifrices, shaving cream, and substances like milk of magnesia.

Example 1 75 g. of potassium iodide or of sodium iodide is incorporated into a dentifrice consisting of 5 kg. of a suspension of magnesium hydroxide in glycerine, 5. kg. of glycerine solidified by means cipitated chalk, 100 cc. of flavoring, and other suitable ingredients, and colored pink by means .of about 0.003% of erythrosin (sodium tetraiodo fluorescein); and when admixture is complete, the smooth paste is packed in the familiar colof about 3% of sodium stearate, 5.2 kg. of pre-- lapsible tin tubes. In a package so constituted,

the erythrosin does not fade, the preparation does not undergo appreciable alteration on account of the tin container, and the tube does not suffer corrosion. 5

, Example 2 50 g. of potassium iodide or of calcium iodide is incorporated into a shaving cream consisting of 4.8 kg. of super-fatted soap, 385 g. of glycerine, 200 g. of lanolin, coloring, odorous, and other suitable ingredients, and water to make 10 kg.; and when admixture is complete, the smooth mass is packed in the familiar collapsible tin tubes. Neither corrosion of the tube nor altera- 16 tion of the contents because of the presence of the tin, takes place in the average, or even in a prolonged, interval between' packaging and consumption. It is to be understood that the foregoing 'ex- 20 amples 'are merely illustrative and not limitative of the invention, which may be variously otherwise embodiedas with respect to the specific alkaline preparations packed in tin containers, the iodides used, and .the procedures followedwithin the scope of the appended claims.

I claim:

1. The method of minimizing interaction between a tin container and an alkaline preparation to be packed therein that comprises incorpo-- 30 rating into the latter an iodide of an element selected from the group consisting of the alkali metals and the alkaline-earthmetals, in amount suflicient to inhibit the alkaline corrosion of the tin container. 35

2. A package comprising a tin container having therein an .alkaline preparation into which there has been incorporated an iodide of an element selected from the group consisting of the alkali metals and the alkaline-earth metals, in amount suflicient to inhibit the alkaline corrosion of the tin container.

3. A package comprising a tin container having therein. an alkaline preparation into which potassium iodide has been incorporated, in amount 45 sufficient to inhibit the alkaline corrosion of the tin container.

4. A package comprising a tin container having therein an alkaline preparation into which sodium iodide has been incorporated, in amount 59 sumcient to inhibit the alkaline corrosion of the tin container.

5. A package comprising a tin container having therein analkaline preparation into which calcium iodide has been incorporated, in amount suflicient to inhibit the alkaline corrosion of the tin container.

6. A package comprising a tin tube having therein an alkaline dentifrice into which there has been incorporated an iodide of an elementselected from the group consisting of the alkali metals and the alkaline-earth metals, in amount sufficient to inhibit the alkaline corrosion of the tin tube.

'7. A package comprising a tin tube having therein an alkaline shaving cream into which there has been incorporated an iodide of an element selected from the group consisting of the alkali metals and the alkaline-earth metals, in amount sufflcient to inhibit the alkaline corrosion of the tin tube.

ANTHONY C. NI'I'II. 

